iTunes Match would have been the best thing I ever used had it come out one (or more) years earlier. Instead, it arrived after I had already tried Spotify, and by then I had tried something better.
I have 15,000 songs in my iTunes library, the vast majority of which are not on Spotify. My 16GB iPhone would normally only hold a fraction of my music but with an iTunes Match subscription I have access to it all.
Also, it gives an off-site back up of every matched song. So tell me, how is iTunes Match similar to Spotify?